let foo;
let bar;
let someType;
let Object;
typeof foo === 'string';
typeof foo === 'object';
typeof foo === 'function';
typeof foo === 'undefined';
typeof foo === 'boolean';
typeof foo === 'number';
typeof foo === 'bigint';
'string' === typeof foo;
'object' === typeof foo;
'function' === typeof foo;
'undefined' === typeof foo;
'boolean' === typeof foo;
'number' === typeof foo;
typeof foo === typeof bar;
typeof foo === baz;
typeof foo !== someType;
typeof bar != someType;
someType === typeof bar;
someType == typeof bar;
typeof foo == 'string';
typeof(foo) === 'string';
typeof(foo) !== 'string';
typeof(foo) == 'string';
typeof(foo) != 'string';
var oddUse = typeof foo + 'thing'
typeof foo === "string"
typeof bar == "undefined"
typeof foo === baz
typeof bar === typeof qux
function f(undefined) { typeof x === undefined }